Endovasular aortic graft

ABSTRACT

An intraluminal prosthesis for intraluminal repair of body conduits, especially aortic aneurysms, is disclosed. The prosthesis includes a generally tubular, flexible graft (20) having a proximal open end (30) and at least one distal open end (31) terminating in a hem (33). A stent (21) can be disposed within the proximal open end (30) and is adapted to be attached to the body conduit (1). The hem (33) is inverted within the graft so that it is disposed as a cuff (34) within the graft. The hem (33) is arranged so that upon withdrawing the distal open end (31) from inside the cuff (34), the cuff will unfold and follow the distal open end to expose it to receive another stent for attachment to the body conduit (12) for intraluminal implantation of the graft. Preferably the hem is folded a second time within the cuff to form a second cuff (35) within the graft. The stents are preferably formed of a plexus of wires adapted to expand from a first narrow diameter to a second diameter to engage the body conduit. Also disclosed is a method of intraluminal implantation of the graft.

This application is a divisional of U.S. patent application Ser. No.08/381,099, filed on Jan. 31, 1995 (status allowed).

FIELD OF THE INVENTION

The present invention relates to an interluminal prosthesis forintraluminal repair of body conduits. More specifically, the presentinvention relates to intraluminal repair of aneurysms using an arterialinterluminal prothesis. Furthermore, the present invention relates to amethod of implanting the interluminal prosthesis in an artery. Theinvention especially relates to an arterial interluminal prosthesishaving a tubular form where one end of the tube is connected to thethoracic aorta and the other end is bifurcated to form two tubularpassageways and each passageway is connectable to each of the iliacarteries.

DESCRIPTION OF THE PRIOR ART

Interluminal devices for repairing body conduits are well known to theart. Such devices include tubular flexible grafts that are implanted bythe use of stents. Stents are a means of attachment of intravascularprostheses.

With special reference to abdominal aortic aneurysms, such aneurysmsoccur because of an abnormal dilation of the wall of the aorta withinthe abdomen. Surgical procedures involving the abdominal wall are majorundertakings with high associated risk together with considerablemortality. The replacement of the aorta with surgical proceduresinvolves replacing the diseased portion of the vessel with a prostheticdevice which is typically formed of a synthetic tube or graft, usuallyfabricated of Dacron®, Teflon®, or other suitable material. In thesurgical procedure, the aorta is exposed through an abdominal incision.The aorta is closed both above and below the aneurysm so that theaneurysm can be opened and any thrombus and arteriosclerotic debris canbe removed. A graft of approximately the size of a normal aorta and issutured in place to replace the aneurysm. Blood flow is thenreestablished through the graft. Surgery according to the prior artrequired an extended recovery period together with difficulties insuturing the graft to the aorta.

In the European patent application to Barone et al., number 0,461,791A1, a method is disclosed for repairing an abdominal aortic aneurysmwhich includes a tubular graft that is intraluminally delivered throughthe iliac artery and secured to the aorta by the expansion anddeformation of a stent. In the application, a tube is disclosed whichhas a single end that is bifurcated to two other ends each of which isattached to one of the iliac arteries. Such disposition of the graft canprovide a reduction in the trauma of the surgery because the graft isdelivered to the site intraluminally. While one connection to an iliacartery is reasonably easy to accomplish, rather complicated techniquesare required to move the other leg of the graft to the other iliacartery and connect it thereto.

A patent to Parodi et al., U.S. Pat. No. 5,219,355, discloses a balloondevice for implanting an aortic interluminal prosthesis to repairaneurysms. In the patent, a graft prothesis is disposed upon a catheterhaving two balloons mounted thereon. The prosthesis is mounted on thecatheter and stents are mounted upon the balloons. The assembly of thegraft, the two balloons and the stents are introduced into the aneurysmby catheterization. The balloons are inflated to implant the prosthesiswithin the aneurysm and affix the stents against the artery walls,thereby to repair the aneurysm. The balloons are deflated and thecatheter is withdrawn.

SUMMARY OF THE INVENTION

According to the present invention I have discovered an interluminalprothesis especially useful for intraluminal repair of aneurysms. Theprothesis includes a generally tubular flexible graft of conventionalprosthetic graft material having a proximal open end and at least oneleg with a distal open end and preferably two legs with two distal openends. Preferably, a first stent is disposed within and attached to theproximal open end. The first stent emerges from the proximal open endand is adapted to be attached to the aorta intraluminally. A hemterminating in the distal open end of the graft is inverted within theleg. The hem is arranged as a cuff within the leg. A second stent havinga proximal and a distal end can be attached to the interior of thedistal end of the cuff so upon withdrawing the second stent from thecuff, the cuff will unfold and follow the stent for implantation of thegraft. In a preferred embodiment the graft is bifurcated at one end toform two legs, each terminating in distal open ends. Each leg isattached to one of the iliac arteries. In the preferred embodiment also,the hem is inverted a second time to form a second cuff within the firstcuff. The stent extends outwardly from the distal open end of the secondcuff. Many of the stents are devices which are deformed by increasingthe diameter until they engage a wall of a body conduit and are anchoredthereto. Alternatively they may be integrally knitted into the graft orthey may be polymeric impregnations of the graft which harden uponheating to enable the hardened impregnation to engage the body conduit.

To dispose the graft within the aorta a conventional guidewire isthreaded through the iliac artery into the aorta using conventionaltechniques. A delivery catheter is then threaded over the guidewireuntil it reaches the desired location within the aorta. A graft havingat least two open ends is disposed on the delivery catheter. Each openend of the graft can have a stent disposed therein. The portion of thegraft that is adapted to be attached to the aorta has the stentextending outwardly from its open end so that the graft may be attachedto the aorta. In the case of a bifurcated graft in which two legs of thegraft are to be attached to the two iliac arteries branching from theaorta, one of the legs can have a stent extending outwardly from itsopen end. The other leg of the graft is disposed inside the graft leg inthe form of a cuff which is inverted into itself at the open end. Astent can be attached to the cuff. A balloon catheter is disposed nearthe end of the inverted leg. The inside of the inverted leg is engagedby the balloon and is withdrawn through the other iliac artery. Whenappropriately positioned within the iliac artery, the stent is expandedto engage the artery and set it. The balloon and then the guidewire isthen withdrawn from the artery and the procedure is completed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevational view partially in cross section of oneembodiment of a bifurcated aortic implant adapted to be disposed withinan aneurysm formed in the aorta and connected to each iliac artery.

FIG. 2 is a side elevational view, partially in cross-section,illustrating another embodiment of an aortic implant.

FIGS. 3 to 10 are a series of views showing a stage-wise progression forperforming a procedure to implant a graft within an aortic aneurysm.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, an arterial interluminal prosthesis 20 forrepairing aneurysms is shown, partially in cross section. The graft orprosthesis, when implanted, has a generally circular cross-sectionalconfiguration. It may be made from a variety of materials provided theyhave requisite strength characteristics to be utilized an aortic graftas well as have requisite compatibility with the human body so that theimplant material will not be rejected. Examples of such material areDacron® and other polyester materials, Teflon®(polytetrafluoroethylene), Teflon® coated with Dacron® material andporous polyethylene urethane. The material can be knitted or woven. Thegraft can also be made of extruded polymeric materials, all of which arewell known to the art as graft materials.

The graft 20 has a proximal open end 30 and two distal open ends 31 and32. The distal open ends are disposed on legs 23 and 24 which bifurcatefrom the graft 20. Each leg preferably is the same length initially,although with some procedures it may be preferable to make the legsaxially stretchable to provide for adjustments in length which may beneeded during implantation. The distal open end 31 of the leg 24 is atthe end of a hem 33 which extends from the edge of the inward fold ofthe leg 24 to the distal open end 31. The length of the leg 24 is notcritical so long as it is adequate to be grasped by a catheter andintraluminally drawn into the iliac artery. A first inversion of the hem33 forms a first cuff 34. In the preferred embodiment the hem 33 isinverted a second time to form a second cuff 35 which opens away fromthe proximal open end 30. Preferably the leg 24 (or both the legs 24 and23) are truncated or tapered with the narrowest diameter being at thedistal open ends to enable the hem to be more easily folded within theleg and form a cuff(s).

A stent is disposed within and attached to the distal open end 31 ofgraft 20. The stent emerges from the distal open end 31 to enable it tobe attached to the iliac artery. Another stent (22) is disposed withinthe leg 23 at its distal open end 32. A third stent (28) is disposed inthe proximal open end 30 to attach to the thoracic artery.

Several types of stents can be used. Common stents are plexuses of wiresthat can be expanded with internal force, such as provided by a balloon,to engage an artery wall. Other stents having applicability includepolymeric expandable structural members and polymeric compositions atthe end of the leg which harden when expanded and activated by heat. Astent can alternatively be constructed as a lining within a graft andextending from one end of the graft to the other to provide for bothfastening of the graft to an artery and its structural stability.

Referring now to FIG. 2, a graft 40 is shown partially in cross-section.In this embodiment the graft 40 is tubular-shaped and does not have twolegs as is disclosed in the previous embodiment. The graft 40 has aproximal open end 41 in which a stent 42 is disposed. The graft 40further has a distal open end 43 disposed at the end of a hem 44. Thehem 44 is inverted within the graft 40 to form a first cuff 45 and inthe preferred embodiment is inverted a second time to form a second cuff46. The second cuff 46 is especially beneficial because it enables thehem 33 to be withdrawn from the leg 24 easily. When a stent is insertedwithin the distal open end 43 it can engage the distal open end 43 todraw the hem 44 outwardly and cause the cuff 45 to unfold and then causethe cuff 46 to unfold also. In this embodiment, as with the embodimentillustrated in FIG. 1, the graft 40 can be truncated or tapered towardthe distal open end to provide for easy inversion of the hem 44 into thegraft 40. In the preferred embodiment, the hem is truncated into twoprogressively narrower diameters or tapered with the distal open end 43having the smallest diameter.

FIGS. 3 to 10 show a portion of the abdominal aortic artery to betreated connected in its upper part with thoracic artery 1 from whichrenal arteries 2 depart. The abdominal aorta presents an aneurysm 5which goes almost to the thoracic aorta 1. The thoracic aorta 1bifurcates at 13 into two iliac arteries 11 and 12.

A conventional guidewire 3 is conventionally threaded into the rightiliac artery 11 into the abdominal aorta through the aneurysm 5 until itreaches the thoracic aorta 1, as shown in FIG. 3.

Referring to FIG. 4, implantation of the graft illustrated in FIG. 1 isshown. A delivery catheter covered by a sleeve 14 is slipped over theguidewire 10 until its distal end is located above the aneurysm 5. Thedelivery catheter includes a hollow center shaft (not shown) covered bythe graft as shown in FIG. 1, the graft being tightly wrapped around thedelivery catheter, as is conventional. The assembly of the deliverycatheter would be the same for the embodiment shown in FIG. 2. If stentsare delivered with the graft, they are collapsed, as is conventionalalso. The graft and stents are covered by the sleeve 14, as isconventional also. After delivery of the graft, it is positioned so thatits proximal open end 30 is above the aneurysm 5. The sleeve 14 iswithdrawn through the iliac artery 11 to leave the graft and stentuncovered. In the embodiment shown, especially in FIG. 5, as the sleeve14 is withdrawn through the artery 11, stent 21 will automaticallyenlarge to engage the aorta wall 1 and as the sleeve 14 is furtherwithdrawn, stent 22 enlarges and engages the interior of artery 11 toanchor the graft 20 in place.

Referring to FIG. 5, the graft 20 is shown expanded and deployed betweenthe thoracic artery 1 and the right iliac artery 11. Stent 21 hasenlarged (or been enlarged) to engage the interior wall of the thoracicartery 1 and hold the graft 20 in place. The second stent 22 is shownengaging the right iliac artery 11 to hold left leg 23 in place. Withthe delivery mechanism illustrated in FIG. 4, the graft 20 has beendelivered with the stents 21 and 22 in place within graft 20. The rightleg 24 of the graft has been inverted within the graft 20 during thedelivery. When the stents are deployed, the right leg 24 will remaininside of the graft 20. Following deployment of the graft 20, theguidewire 10 and center shaft 25 (upon which the graft 20 was mountedwhen the device was deployed within the artery) is withdrawn through theright iliac artery 11.

As shown in FIG. 6, a catheter 26 is inserted into the left iliac artery12 and directed into right leg 24 that is inverted in the graft 20. Oneof the more suitable means for engaging the leg 24 is a cathetercarrying a balloon 37 with a stent mounted upon it (if the leg 24 wasnot implanted with a stent already in place). Enlargement of the balloon37 will enlarge the stent sufficiently to enable the stent to grasp theinside of the leg 24 and withdraw it through itself. Alternatively, acatheter with a stent mounted on it can be inserted into the leg 24after it has been drawn into the left iliac artery 12. Another mechanismto withdraw the leg is to insert a hook which will engage the invertedleg. The stent can be enlarged as described above.

As shown in FIG. 7, the catheter 26 that was inserted into the leftiliac artery 12 to engage the distal open end of the leg 24 is beingwithdrawn from within the graft 20 by drawing catheter 26 through theartery 12. The distal open end and the inverted leg 24 will follow it.When the inverted leg 24 is fully withdrawn, one of several techniquescan be used to implant the stent. In one technique, the stent isdeployed upon a balloon catheter and inflation of the balloon (when thestent is in a correct position in the left iliac artery 12) will causethe stent to be seated. Another approach involves a stent disposedwithin the leg 24 while it is inverted within the graft 20. In thisapproach, when the leg 24 is drawn from the graft 20 the stent willemerge and enlarge automatically as the leg 24 is drawn out. Moreoverthe stent can be a polymeric impregnation of the leg, as mentionedabove. Expansion of the leg 24 against the artery and heating willstiffen the leg 24 to implant the prosthesis.

In FIG. 8 the balloon catheter is shown enlarging the stent to it in theiliac artery 12. FIG. 9 shows the balloon catheter being moved from theposition within the stent 28 just immediately prior to withdrawal of thecatheter 26 from the iliac artery. The balloon can be deflated to allowfor easy withdrawal of the catheter from the stent and through theartery.

FIG. 10 shows the graft 20 implanted between the two iliac arteries 11and 12 and the thoracic aorta 1. A stent 22 anchors the left leg 23 ofthe graft 20 to the right iliac artery 11 and a stent 28 anchors theright leg 24 to the left iliac artery 12. The aneurysm 5 surrounds thegraft but does not receive blood into it. Drainage of the aneurysm canbe accomplished percutaneously or otherwise, as is conventional.

The graft depicted in FIG. 2 of the drawings having only one distal openend can be deployed and implanted similarly as the embodiment shown inFIG. 1, except the procedure is less complicated in that the procedurerequires entering through only one of the iliac arteries.

While it is apparent that changes and modifications can be made withinthe spirit and scope of the present invention, it is my intention,however, only to be limited by the appended claims.

As my invention I claim:
 1. A method of intraluminally implanting agraft within a body lumen, said method comprising:intraluminallyinserting in a body conduit a generally tubular, flexible graft with aproximal open end and at least one distal open end and a first stentdisposed within and attached to said proximal open end and emergingtherefrom and wherein said distal open end of said graft is invertedwithin said tubular graft such that said distal end is arranged as acuff within said graft; locating said graft in a predetermined positionwithin said body lumen; expanding said first stent and attaching it tosaid body lumen; intraluminally engaging said cuff and withdrawing saiddistal open end from inside said cuff thereby unfolding said cuff fromwithin said distal end of said graft; enlarging the internal diameter ofa second stent disposed within said distal open end and attaching saidsecond stent to said body lumen thereby implanting said graft.
 2. Themethod according to claim 1 wherein said second stent is disposed withinsaid cuff and emerges from said distal open end and said cuff iswithdrawn by engaging said second stent.
 3. A method of intraluminallyimplanting a graft within an aorta, said methodcomprising:intraluminally inserting in an iliac artery branching fromsaid aorta a generally tubular, flexible graft with a proximal open endand with at least one distal open end and with a first stent disposedwithin and attached to said proximal open end and emerging therefrom andwherein said distal open end of said graft includes a hem, said hembeing inverted within said tubular graft such that said hem is arrangedas a cuff within said graft; locating the proximal open end of saidgraft in a predetermined position within said aorta; expanding saidfirst stent and attaching it to said aorta; intraluminally engaging saidhem and withdrawing it from inside said cuff and drawing it into aniliac artery thereby unfolding said cuff from within said distal end ofsaid graft; expanding a second stent and attaching it to the iliacartery into which it was withdrawn thereby implanting said graft.
 4. Amethod of intraluminally implanting a graft within an aorta, said methodcomprising:intraluminally inserting into one of two iliac arterybranching from said aorta a generally tubular, flexible graft with aproximal open end and with two distal open ends on two legs branchingfrom said graft and with a first stent disposed within said proximalopen end and emerging therefrom and wherein there is another stentdisposed on a hem of one of said legs of said graft and emergingtherefrom and wherein a hem on the other of said legs is inverted withinsaid other leg to form a cuff within said other leg; locating theproximal open end of said graft in a predetermined position within saidaorta; expanding said first stent and attaching it to said aorta;intraluminally engaging said another stent and expanding it to attach itto the iliac artery through which said graft was inserted;intraluminally engaging said cuff through said other iliac artery andwithdrawing it from inside said leg and drawing it into said other iliacartery thereby unfolding said cuff from within said distal end of saidgraft; expanding another stent and attaching it to said other iliacartery thereby implanting said graft.
 5. The method according to claim 4wherein said hem on the other of said legs is folded a second timewithin said cuff to form a second cuff within said distal open end. 6.The method according to claim 4 wherein said stents are formed of aself-expanding plexus of wires adapted to expand from a first narrowdiameter to a second diameter or of a plexus of wires that is expandableby the application of interior force to a larger internal diameter toengage said body conduit.